#include <iostream>

using namespace std;

double division(double a, double b)
{
    if (b == 0)
    {
        throw "can't divid by zero";
    }
    return a / b;
}

int main()
{
    double x, y, z;
    x = 20, y = 0;
    try
    {
        z = division(x, y);
        cout<<z<<endl;
    }
    catch (const char* msg)
    {
        cerr << msg << '\n';
    }

    return 0;
}